package com.maishi.programmer.jainzhioffer;

/**
 * Created by brossdong on 2018/3/28.
 * 输入两棵二叉树A，B，判断B是不是A的子结构。
 * （ps：我们约定空树不是任意一个树的子结构）
 */
public class TestProblem26 {

    public class TreeNode {
        int val = 0;
        TreeNode left = null;
        TreeNode right = null;
        TreeNode (int val) {
            this.val = val;
        }
    }

    public boolean HasSubtree(TreeNode root1,TreeNode root2) {
        boolean flag = false;
        if (root1 != null && root2 != null) {
            if (root1.val == root2.val) {
                flag = Tree1HasTree2(root1,root2);
            }
            if (!flag) {
                flag = Tree1HasTree2(root1.left,root2);
            }
            if (!flag) {
                flag = Tree1HasTree2(root1.right,root2);
            }
        }

        return flag;
    }

    private boolean Tree1HasTree2 (TreeNode root1,TreeNode root2) {
        if (root1 == null) return false;
        if (root2 == null) return true;
        if (root1.val != root2.val) return false;
        return Tree1HasTree2(root1.left,root2.left) && Tree1HasTree2(root1.right,root2.right);
    }


}
